Adjustable mechanism for posture chairs



June 8, 1954 A. J. FRITZ 2,680,474 ADJUSTABLE MEcHANIsM FOR PosTURE CHAIRS Filed June 24, 1950 lll' drawings in which:

Patented June 8, ,1954

UNITED STATES PATENT OFFICE ADJUSTABLE MECHANISM FOR POSTURE CHAIRS Arthur J. Fritz, Evansville, Ind. Application June 24, 1950, Serial No. 170,198 4 Claims. (Cl. 155-157) Still another object of my invention is to provide a composite constructionof hardware adapted to be mounted beneath a chair seat and serving both as a cradle for a compression spring adapted to yieldably support Vthe chair seat and also as a selectively adjustable means for a bracket member operative to support a back rest in selected position with respect to the chair seat.

A further object of my invention is to provide a novel construction of clamp mounted beneath a chair seat for selectively positioning a back rest with respect to the chair seat.

Other and further objects of my invention will be understood frcin the specification hereinafter following by reference to the accompanying invention; Fig. 7 is a perspective View from a minimum number of y ported in the U manufactured and assembled on a mass production scale inexpensively for providing all of the posture chair.

Referring to the drawings in more detail the assembled posture chair is shown in Fig. 1 including a multiplicity of legs I terminating in casters 2. The legs I are connected with a central frame The adjusting screw 3 isy supshaped bracket 5 which is mounted by the angle members 6 secured to the bottom of the seat verse pivot bar I0 as a center.

The housing I I is formed by a casting which includes av pair of longitudinally extending cylindrical passages I2 and I4 disposed on spaced parallel axes terminating at their ends in transversely disposed lugs I5 and I6 projecting in one direction and transversely disposed integrally connected stops I5b and Ib extending in the opposite direction, with respect to the axes of cylin drical passages I2 and I3. The transversely extending lugs I5 and I6 are apertured at I5a and IGa for receiving the transverse pivot bar I which extends therethrough and provides the pivot means about which housing II may rock or rotate within limits. The angular movement of housing II is controlled in one direction by the stops I5b and Ib and the abutment thereof disposed semi-cylindrical slots extend through the cylindrical passages I 2 and I4 as shown more clearly in Fig. 7. The semi-cylindrical slots I'I and I8 are transversely aligned for the passage of the transversely extending pressure bar I9.

The pressure bar I9 is provided with an aperture I 9a therethrough which is alignable With the screw threaded recess 20a in the centrally disface of channel shaped member Il.

Wardly therethrough as shown more particularly in Fig. 3 and is provided with a manipulating knob 22 thereon which may be grasped by the fingers or by means of a tool for adjusting screw 2| through spacing cylindrical sleeve 23 and aperture Ic in pressure bar I9. The pressure bar I9 extends transversely across the longitudinal paths of the cylindrical passages I2 and I4 through the semi-cylindrical slots II and I6 and establishes tangential contact with the surfaces of the tubular frame members 25 and 21.

The tubular frame members 26 and 2l are suitably interconnected in a transverse direction Iand are adapted to move into and out of the cylindrical passages I2 and III to selected positions. The tubular frame members 26 and 2l serve as carriers for the adjustable back cradle 28 forming an adjustable support for the back rest 2S for the posture chair. The tubular frame inembers 2% and 21 may be moved telescopically into or out of cylindrical passa-ges I2 and M for properly positioning the back rest 23 with respect to the rear peripheral edge of the seat l.

The housing II is provided in a position adjacent the forward end thereof with a cylindrical pocket 2d extending on a vertical axis aligned with the central axis of housing I I and extending both above and below the cylindrical passages I2 and Ill.V The cylindrical pocket 2li receives the compression coil spring 25 which bears against the interior end of the cylindrical pocket 213 and the central interior face of the channel shaped member Si. The `compression coil spring 25 as thus mounted tends to continuously urge the housing II in a clockwise direction as viewed in Fig. 3. The force of the compression spring 25 resists the back pressure exerted by the occupant of the posture chair in leaning backward against the back rest 29. The occupant in leaning against the back rest 29 tends to shift housing II in a counter-clockwise direction against the force of compression coil spring 25. The maximum angle to which back rest 2S may be moved is limited by abutment oi the top of the cylindrical pocket 24 with the central interior surface of channel shaped member 9. The maximum position to which back rest 2Q may be thrust by the action by compression coil spring 25 is limited by abutment ci stops leb and Iib with the inside sur- Adjusting screw 2! when rotated in a counter-clockwise d'1- rection releases pressure bar i9 from pressure contact with the surfaces or" tubular frame members 23 and 2l permitting the tubular frame members to be adjusted in position axially of the cylindrical passages I2 and III for shifting the back rest 29 to a selected position with respect to the rear peripheral edge oi seat l. lN'lien the proper position has been selected adjusting Vscrew 2I is revolved in a clockwise direction thereby applying pressure bar I9 against tubular frame members 28 and 21 and introducing the necessary clamping pressure for xing the back rest 29 in desired position with respect to the seat oi the posture chair.

I have found the adjustable mechanism which mounts beneath the chair seat as herein described highly practical in construction and economical in manufacture and assembly on a mass production scale and although I have described my invention in one of its preferred embodiments I realize that modifications may be made and I desire that it be understood that no limitations What I claim as new and desire to secure by Letters Patent of the United States is as follows:

1. A device for connecting a chair back with a chair seat comprising a relatively at support, a channel shaped member having a flat central portion and a pair ci depending side portions, said flat central portion being attached to the under surace of said relatively flat support, a housing extending longitudinally through said channel shaped member within the protective connes of said depending side portions, means disposed adjacent one end oi said channel shaped member and extending through said side portions for journalling said housing, said housing including a pair of spaced tubular members extending substantially the length of the housing with longitudinally extending bores therein, frame members slidably adjustable through said bores, the walls of said tubular members having transverse slots therein adjacent said journalling means, an adjustable screw extending through said housing intermediate said tubular members, a pressure bar carried by said screw and operative through the transverse slots in said housing for selectively engaging said frame members in a selectively adjusted position, a coil spring aligned with the central longitudinal axis of said housing and extending between the flat central portion of said channel member and one end of said housing and abutment stops carried by the other end of said housing and cngageable with the flat central portion of the other end of said channel shaped member for limiting the angular movement of said housing about said journaliing means.

2. A device for connecting a chair back with a chair seat as set forth in claim 1 wherein said adjustable screw engages said housing in a position intermediate the journal o said housing in upon my invention are intended other than may be imposed by the scope of the appended claims.

the depending side portions of said channel shaped mem :er and the position at which said coil spring engages the dat central portion of said channel shaped member.

3. A device for connecting a chair back with a chair seat as set iorth in claim 1 wherein said abutment stops carried by said housing are integral with the upper surfaces of the terminating ends ci said tubular members and abut with the end of the nat central portion of said channel shaped member in positions adjacent the inner faces ci said depending side portions oi said channel. shaped member.

e. A device for connecting a chair back with a chair seat as set forth in claim 1 in which said tubular members are cylindrical and the frame members that are adjustable therein are of corresponding circular section, said pressure bar being substantially fiat and extending substantially within the limits of the thickness of the Walls of the tubular members and establishing tangential contact with the surfaces of said fra-mc members in a position intermediate the journal at one end of said housing and the coil spring at the other end thereof.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 758,133 Gilson Apr. 26, i904 899,504 Bclens Sept. 29, 1908 FOREIGN PATENTS Number Country Date 233,519 Great Britain May, 14, 1925 523,720 Germany Apr, 27, 1931 

